For The Lemon Filling, Place The Sugar, Flour, And Salt In A Medium-Size Saucepan, And Stir To Combine.
Beat The Egg Yolks With The Water And Lemon Juice And Whisk Into The Dry Ingredients.
Stir And Cook Over Medium-High Heat Until The Mixture Comes To A Boil, Then Reduce The Heat To Medium And Whisk And Cook For 2 Minutes More.
Remove The Pan From The Heat, And Whisk In The Zest And Butter.
Pour The Filling Into A Bowl, And Cover With Plastic Wrap.
Chill In The Refrigerator Until It Is Thick And Spreadable, About 3 Hours.
For The Cake, Place A Rack In The Center Of The Oven, And Preheat The Oven To 350°F.
Lightly Grease And Flour Three 9″ Cake Pans, And Shake Out The Excess Flour.
Set The Pans Aside.
Crack The Eggs Into A Large Mixing Bowl, And Beat With An Electric Mixer On Medium Speed For 30 Seconds To Combine.
Gradually Add The Sugar While Beating Until Fluffy, 2 To 3 Minutes More.
Set The Mixture Aside.
Sift The 2 Cups Of Flour Twice, And Then Add To The Egg Mixture A Little At A Time, Beating On Low Speed Until Just Combined, 30 To 45 Seconds.
Place The Milk And Butter In A Medium-Size Saucepan Over Medium-High Heat.
Stir Until The Butter Melts And The Mixture Comes Just To A Boil, About 4 Minutes.
Slowly Pour The Butter And Milk Into The Batter While Beating On Medium Speed Until Smooth, 3 To 4 Minutes.
The Batter Will Be Thin.
Sift The Remaining 1 Tablespoon Flour With The Baking Powder And Salt, And Beat On Low Speed Into The Batter With The Vanilla And Almond Extract Until Just Combined, 1 Minute.
Divide The Batter Between The Prepared Pans, And Place The Pans In The Oven.
If Your Oven Is Not Large Enough To Place 3 Pans On One Rack, Place 2 On The Center Rack, And Place 1 Pan On The Rack Above, Watching To Make Sure The Cake Does Not Overbake.
Bake The Cake Until It Is Lightly Golden Brown, 18 To 22 Minutes.
Remove The Layers From The Oven, And Place Them On Wire Racks To Cool For 10 Minutes.
Run A Knife Around The Edges Of The Pans, Give The Pans A Gentle Shake, And Invert The Cakes Once And Then Again So They Rest Right Side Up On The Racks To Completely Cool, 30 Minutes.
To Assemble The Cake, Place 1 Layer On A Cake Plate Or Platter And Spread Half Of The Filling To Within ½” Of The Edges.
Top With A Second Layer, And Spread With The Other Half Of The Filling.
Place The Third Layer On Top.
Place These Layers And Filling Back Into The Refrigerator To Chill For 30 Minutes.
While The Cake Is Chilling, Make The Icing.
To Finish The Assembly, Remove The Cake From The Refrigerator, And Frost The Top And Sides Of The Cake.
Slice And Serve.
